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1.
The piston cooling valve opens when engine
speed has just reached above low idle and oil pres-
sure has increased. The oil is then led by a drilling
to the piston cooling duct in the engine block. Six
nozzles are connected to the piston cooling duct,
one for each piston, and from these oil is sprayed
against the bottom of the pistons.
2.
The relief valve for the oil filters opens if the fil-
ters are clogged. This ensures continued lubrica-
tion.
3.
The by-pass valve opens when the pressure drop
across the oil cooler is too high, e.g., at cold start.
When the valve opens, the oil by-passes the oil
cooler to get more quickly out to the engine lube
points.
4.
The reducer valve opens at excessive lube oil
pressure to return the excess oil back to the sump.
The engine is lubricated from a pressure-lubricating
system. Since the engine lies horizontally, the oil sump
is of the dry type with separate oil tank.
The oil system delivery pump sucks the oil from the oil
tank through a strainer. It then pressurizes the oil out to
the various lube points in the lubricating system.
Return oil is pumped back to the oil tank by two scav-
enging pumps.
General layout, engine oil
The oil pump is of the gear type and has
three pump units. The front unit functions
as an oil delivery pump and the other two
as scavenging pumps. They all pump the
oil back to the oil tank via the oil cooler.
The oil pumps are gear-driven from the
crankshaft via an intermediate drive gear.
The lubricating oil filters have “spin-on”
type replaceable filter inserts.
The high capacity of the oil pump places
greater demands for greater lube oil filtra-
tion. It is for this reason that the engines
have two full-flow oil filters (direct oil fil-
ters and no by-pass filter). The full-flow
filters are coupled in parallel for best
filtration.Oil pump
drive gearScavenging
10
2
A
B
1
11
12
13
3
7
4
5
6
8
8
9
1
3
2
